Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic EPS [Abstract]
Weighted average common shares outstanding (in shares)	43,360	43,643	43,464	43,704
Net income available to common stockholders	$ 37,433	$ 35,113	$ 117,575	$ 70,194
Basic EPS (in dollars per share)	$ 0.86	$ 0.80	$ 2.71	$ 1.61
Diluted EPS [Abstract]
Weighted average common shares outstanding (in shares)	43,360	43,643	43,464	43,704
Dilutive effect of common stock options and restricted stock (in shares)	271	299	305	293
Weighted average common shares and common share equivalents (in shares)	43,631	43,942	43,769	43,997
Net income available to common stockholders	$ 37,433	$ 35,113	$ 117,575	$ 70,194
Diluted EPS (in dollars per share)	$ 0.86	$ 0.80	$ 2.69	$ 1.60